Dental instrument lubricant



Patented Mar. 5, 1946 2,396,192 DENTAL INSTRUMENT LUBRICANT John D. Morgan, South Orange, and Russell E. Lowe, East Orange, N. 5., assignors to Cities Service Oil Company, New York, N. Y., a corporation of Pennsylvania No Drawing. Application July 26, 1944,

' Serial No. 546,735

4 Claims. (Cl. baa-5e) This invention relates to lubricants and more particularly to special oils for lubricating dental instruments and equipment.

The lubrication of the bearing and other moving parts of high speed dental drills, for example, raises problems which are not met in conventional lubrication work. The prime requisite of an oil for such work is, of course, that it shall have good enough lubricating properties to reduce frictional losses and wear to a minimum. The oil should also be chemically stable, resisting oxidation and remaining free of gums in the presence of saliva and common mouth acids. Other required properties of the lubricant. however, are

largely determined by the fact that dental drills and instruments are used in close proximity to the patients nose and eyes, and, of course, within his mouth. Thus the oil must be substantially colorless so that the instruments will not give the appearance of being dirty and greasy, and will not leave smudges on the patients face. A somewhat similar requirement is that the oil shall be odorless. On this score. it is amatter of common knowledge that dental patients are inclined to be nervous and irritable. The fairly strong odor given oil by ordinary petroleum oils tends further to aggravate the patient, and for this reason such oils are not preferred for the lubrication of dental instruments.

The principal object of this invention is to provide a dental lubricating oil which will meet the requirement outlined above and overcome all of the objections to the use of ordinary dental lubricants.

We have discovered that an entirely satisfactory dental instrument'lubricant can be prepared using the colorless fractions of a neutral lubricating oil as a base. These fractions. havin an average viscosity of about '76 S. U. V. at 100 F.. are too li ht in body to provide adequate lubrication for dental drills. for example. In order to overcome this deficienc we add 'a thickening agent in suflicient quantities to increase the viscosity of the mixture to about 100 S. U. V. at 100 F. For this purpose we prefer to use a mixture of equal parts of octyl and decyl esters of metacrylic acid polymerized to a molecular weight of about 15,000. and we have found that the addition of from 2 to 4 percent of this agent is sufiicient for ordinary purposes.

The resulting product has the character of a light spindle oil which is capable of working its way into the bearings of a dental drill, and yet is not so fluid as to cause it to drip-from such instruments when they are being used. The mixture of mineral oil and methacrylic polymer is substantially colorless and odorless, thus meeting these requirements of a satisfactory dental lubricant. In this connection, however, we preier to add a trace of synthetic oil of roses which gives the product an appreciable and pleasant odor. It should be noted, however, that the oil of roses serves only as an odorant and it may accordingly be omitted if desired.

In preparing a specific dental instrument lubri cant in accordance with our invention, we subjected a well refined Mid-Continent Oil having a viscosity of about 72.5 S. U. V. at 100 F., flash point 375 F. to chromatographic separation, without solvent dilution. The following fractions,

each having an N. P. .A. color of less than one;

were then blended together to provide 97.7% by volume of the final composition:

Fraction Viscosity Gravity Seconds 72. 0 0. 75. 5 30. 96 3/4. 73. 5 33. 42 0 plus 77. 5 33. 42 0 plus 77. 0 32. 46 H2. 80. 0 30. 87 3/4. 81. 5 31. 52 0 plus '76. 5 32. 27

' lubrication. The odor was negligible, being only that of faint rose perfume. The N. P. A. color of the product was about one-half, which, as can be appreciated, is very low indeed. Its presence on dental instruments is all but unnoticeable-a "must for dental oils 'as has been pointed out above. The flash point, Cleveland open cup, for the product was 370 F. and the fire point 400 F. Both of these critical points are well above any temperatures normally encountered in dental instrument lubrication and are considerably in ex cess of usual specifications for dental oils.

We prefer to employ a chromatographic separation process for decolorization purposes, because that process removes both free gum and polymer, just as was described above, and enough oil of roses can be added to give the composition an appropriate bouquet.

The percentages of mineral oil and methacrylic polymer which have been given in the foregoing example are fairly critical, and should be closely followed to obtain a product having the I desired viscosity and gravity. Some slight variations, within the ran es stated. are permissible,

however. Insofar as the oil of roses is concerned, it serves only as an odorant, as has been indicated, and it maybe-included or omitted in accordance with the dictates of individual cases. I Having described-our invention in its preferred form, what we claim is:

1. A dental instrument oil consisting essentially of a major portion oi a decolorized mineral oil having an average viscosity of about 72 S. U.-V. at 100 F., and a minor portion ofa mixture of equal parts of octyl and decyl esters of methacrylic acid polymerized to a molecular weight of approximately 5.0 the pro t ons of the oil and methacryllc polymer beingsuch that the final product has a viscosity of about 100 S. U. V. at 100 F. v

2. A dental instrument oil consisting essentially of a blend of the chromatographicallyseparated fractions of a neutral mineral-oil which are substantially odorless and have an average ates-w viscosity ofaboutflt s. u. v. 100- .rg a asl mixture of equal parts of octyl anddecyl-esters of methacrylic acid polymerized to a molecular weight of about 15,000; said blend representing from about 96 percent to 98 percent by volume of the composition, and said methacrylic polymer from about 4 percent to 2 percent of'said composition. v

3. A dental instrument oil consisting essentially or a blend 0! the chromatographically; separated fractions of a neutral mineral oil having a viscosity of about 72 B. U. V. at 100 F., said fractions having an N. P.-A..color of less than one and an average viscosity of about '16 8. U. V. at 100 It; and a mixturefofaqual parts of octyl and -decyi esters of methacrylic acid polymerized to a molecular weight or about 15,000; said blend representing about 96 percent to 98 percent by voTume of-the composition, and said methacrylic polymer about 4- percent to 2 percent of such composition. a a 4. A dental instrument oil consisting essentially of a blend of the chromatographically separated i'ractions of a neutral mineral oil having a, viscosity of about 72 S. U. V at 100 F.. said fractions having an N. P. A. color of less than one and an average viscosity of about 76 S. U. V. at 100 F.:

and a' mixture of equal parts of octyl and decyl esters of methacrylic acid polymerized to a molecular. weight of about 15.000; and minute quantities of synthetic oil of roses; said blend representing about 96.7 percent by volume of the entire composition, said methacrylic polymer about 3.25 percent, by volume, and said synthetic oil of I roses about 0.05% by volume. V

JOHND. uoaean. possum. 2:. LOW. 

